Hey! I used to live with a drummer, and two important things to pay attention to are leaving some sort of space in the wall, dead air, and also, heating vents can be a problem because they channel the noise right into every room in the house...The spaces in the wall act as deadeners, apparently. You might try calling some local recording studios too.

Acoustical Solutions carries a floor underlayment that helps with both airborne and bass, vibrational or structural noises. It is an environmentally friendly rubber based product made from recycled tires and also has a sound barrier included. It can be installed over wood and concrete, under hardwood, vinyl, tile and carpet.

-Donnie, Acoustical Solutions, Inc.